The biggest issue is that the micro usb port is surface mounted onto the board. There's always a risk involved with replacing one because the tracks are fine and can be damaged. The battery will be the harder part to source unfortunately. You need to find the appropriate battery that's suitable for them. They were never really meant to be repaired; most things aren't these days.

Thanks guys for the advice.
I know USB is a major problem, precision required. Also may need to buy new micro ports.
As for batteries, I will dismantle one unit and see what kind of batteries are required and start looking around.

The question remains, is there anyone willing to do it, provided that I find the parts.
Will pay of course.